Feeder for uniformly supplying a mixture of particulate solids

ABSTRACT

A minimally-shearing feeder mechanism supplies a desired flow of particulate solids mixture, with minimal to no sifting segregation, to a desired location. The feeder mechanism maintains a uniform concentration of each size of particle within the mixture.

RELATED APPLICATIONS

This application is a division of and claims the benefit of U.S. patentapplication Ser. No. 11/304,424, filed Dec. 15, 2005, which is expresslyand entirely incorporated herein by reference.

This application is being filed in conjunction with, and in addition to,divisional U.S. patent application Ser. No. ______ (Attorney DocketNumber JJK-046DV1) and divisional U.S. patent application Ser. No.______ (Attorney Docket Number JJK-046DV3), all of which claim priorityto the above-identified pending patent application.

FIELD OF THE INVENTION

The present invention relates to a feeder mechanism, and moreparticularly to a minimally-shearing feeder mechanism that regulates andcontrols the supply of a particulate mixture received from a supplyhopper.

BACKGROUND OF THE INVENTION

Mixtures of solid particles can separate or segregate during handling.The non-uniformity of the mixture can result in quality controlproblems, such as the waste of raw materials, lost production, andincreased maintenance and capital costs required to retrofit existingfacilities where unwanted segregation of solid particle flows isoccurring. Segregation problems can occur with a number of differenttypes of solid particle mixtures, including larger particles, such ascoal or rocks, to smaller particles, such as powders, includingpharmaceutical powders.

Segregation can occur in a number of different ways, based primarily onvarious physical properties of the mixture and environmental or handlingconditions. Sifting is a prevalent form of segregation. Sifting can bedefined as the movement of smaller particles through a mixture of largerparticles. This can occur during formation of a pile, as smallerparticles percolate into the pile, while coarse particles slide or rollto the perimeter of the pile. In order for sifting segregation to occur,several conditions are required. There must be a difference in particlesize, for example, ratios as small as 1.3:1 can induce siftingsegregation. Sifting is generally most pronounced when the mean particlediameter is greater than 100 microns. The mixture must be sufficientlyfree flowing to allow interparticle motion. Finally, there must bemovement of the particles relative to one another or portions of theflow within the mixture.

Bulk storage containers, such as hoppers, silos, bunkers and bins, areconventionally used for the storage of quantities of loose particulatesolids, including particulate solid mixtures. For the purposes of thepresent application, the term “hopper” will be used to cover all suchdiffering forms of storage containers for particulate material, wherethe material fills or partially fills the container and moves during thedischarge process to an outlet situated in the lower regions of thecontainer. If all of the material is in motion during discharge, this isreferred to as mass flow of the material.

Bulk solids are generally comprised of particles of different sizes. Itis commonly desirable to maintain a uniform concentration of each sizethroughout the mixture during industrial processing, storage, andpackaging. However, segregation of the particles by size frequentlyoccurs during processing steps such as the filling or discharge of ahopper. Such actions can lead to segregation by sifting. Accordingly,different regions within a mixture of particulate solids within a hoppercan have different proportions of fine and coarse particles. Thus,uniformity of the mixture is lost.

For numerous reasons it can be desirable to be able to handle and movebulk solids with different size particles while maintaining a uniformconcentration of each size, including sampling, measurement, and testingprocesses as well as general handling of the material. Feeder mechanismscan be utilized to supply mixtures of bulk solids to hoppers or otherlocations.

SUMMARY OF THE INVENTION

There is a need for a feeder mechanism that maintains a good mixture ofsolid particulates of different size and composition for processes suchas segregation testing and the like. The present invention is directedtoward further solutions to address this need.

In accordance with one example embodiment of the present invention, afeeder for a mixture of particulate solids includes a fixed bottom platehaving a discharge aperture therethrough. A second plate is rotatablyslidable over the bottom plate, and has a plurality of pass throughapertures disposed therein. Its rotational axis is spaced to cause theplurality of apertures to pass sequentially over the discharge apertureof the bottom plate. A deposition aperture is configured to receive themixture and deposit the mixture on the rotatable second plate in adeposited trail as the second plate rotates. A fixed cam plate isslidably mounted over the rotatable second plate; the cam plate having acontoured periphery configured to displace the deposited trail radiallyand progressively outward to the pass through apertures of the secondplate as the second plate rotates, supplying the mixture forming thedeposited trail to the discharge aperture.

In accordance with aspects of the present invention, the depositionaperture is integral with the cam plate. The plurality of pass throughapertures are uniformly spaced. The plurality of pass through aperturescan have equal dimensions to one another. The plurality of pass throughapertures can likewise be sized sufficiently large enough to prohibitthe mixture from arching over the pass through aperture due to particlesize or particle cohesion. The plurality of pass through apertures canfurther be disposed in a substantially circular pattern in the secondplate. The second plate can have a substantially circular shape. Theplurality of apertures can be disposed along a periphery of the secondplate.

In accordance with further aspects of the present invention, thedeposited trail is of uniform cross-section. The cam plate can beconfigured to displace the deposited trail radially and progressivelyoutward with minimal shearing of the mixture forming the depositedtrail. A supply hopper can be disposed to supply the mixture ofparticulate solids to the feeder. A motor can be configured to rotatablydrive the second plate. The second plate can rotate at a rate of betweenabout 2 RPM and about 20 RPM. The feeder can supply a substantiallyconstant stream of the mixture through the discharge aperture.

In accordance with one embodiment of the present invention, a method ofuniformly supplying a mixture of particulate solids includes receiving asupply of the mixture from a supply source. The mixture is directed to adeposition aperture configured to receive the mixture and deposit themixture on a rotating plate in the form of a deposited trail as therotating plate rotates. The deposited trail is displaced radially andprogressively outwardly along the rotating plate to a plurality of passthrough apertures disposed in the plate. The mixture is discharged fromthe plurality of pass through apertures and through a dischargeaperture.

In accordance with aspects of the present invention, the supply sourcecomprises a bin or hopper. The deposition aperture can be disposed in afixed cam plate slidably mounted over the rotating plate. Displacing thedeposited trail can include forming the deposited trail on the rotatingplate with a uniform cross-sectional area. Displacing the depositedtrail can further include using a fixed cam plate having a contouredperiphery configured to displace the deposited trail radially andprogressively outward to the plurality of pass through apertures of therotating plate as the rotating plate rotates, supplying the mixtureforming the deposited trail to the discharge aperture. The cam plate canbe configured to displace the deposited trail radially and progressivelyoutward with minimal shearing of the mixture forming the depositedtrail.

In accordance with further aspects of the present invention, the methodcan include rotating the rotating plate at a rate that at leastsubstantially hinders the mixture from arching over the plurality ofpass through apertures. The rotating plate can rotate at a rate ofbetween about 2 RPM and about 20 RPM. A motor can drive the rotatingplate. The feeder can supply a substantially constant stream of themixture through the discharge aperture.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become better understood with reference tothe following description and accompanying drawings, wherein:

FIG. 1 is a diagrammatic illustration of a segregation testingapparatus, according to one embodiment of the present invention;

FIG. 2 is a perspective illustration of a channel hopper portion of thetesting apparatus, according to one aspect of the present invention;

FIGS. 3A, 3B, 3C, and 3D are front view, top view, bottom view, and sideview, respectively, of the channel hopper of FIG. 2, according to oneaspect of the present invention;

FIG. 4 is a diagrammatic illustration of the channel hopper partiallyfilled with mixture for testing, according to one aspect of the presentinvention;

FIG. 5 is a perspective illustration of a collector portion of thetesting apparatus, according to one aspect of the present invention;

FIG. 6 is a perspective illustration of an alternative collector portionof the testing apparatus, according to one aspect of the presentinvention;

FIGS. 6A, 6B, 6C, 6D, and 6E are side view illustrations of thecollector portion of FIG. 6, according to one aspect of the presentinvention;

FIG. 7 is a perspective illustration of a feeder mechanism portion ofthe testing apparatus, according to one aspect of the present invention;

FIG. 8 is a perspective illustration of a cam portion of the feedermechanism of FIG. 7, according to one aspect of the present invention;and

FIG. 9 is a diagrammatic illustration of a basic sampling procedure,according to one aspect of the present invention.

DETAILED DESCRIPTION

An illustrative embodiment of the present invention relates to aspecialized feeder mechanism, which provides a steady minimally-shearingsupply of the mixture to, for example, a channel hopper. The feedermechanism can vary in speed, thus varying flow rate of the mixture asdesired. The feeder mechanism further operates with minimal siftingsegregation of the mixture as it passes through the feeder mechanism tothe channel hopper. Prior to entering the feeder mechanism, the mixtureis well mixed by some means unrelated to the apparatus of the presentinvention. The operation of feeding the mixture with the feedermechanism from a supply hopper to the channel hopper for testingprovides minimal disruption of the mixture, while simultaneouslyenabling regulation and control of the mixture feed to the channelhopper.

FIGS. 1 through 9, wherein like parts are designated by like referencenumerals throughout, illustrate example embodiments of a particulatesolids mixture segregation testing apparatus and corresponding method ofuse, and a feeder mechanism and method of use according to the presentinvention. Although the present invention will be described withreference to the example embodiments illustrated in the figures, itshall be understood that many alternative forms can embody the presentinvention. One of ordinary skill in the art will additionally appreciatedifferent ways to alter the parameters of the embodiments disclosed,such as the size, shape, or type of elements or materials, in a mannerstill in keeping with the spirit and scope of the present invention.

FIG. 1 is a diagrammatic illustration of a particulate solids mixturesegregation testing apparatus 10 in accordance with one embodiment ofthe present invention. The testing apparatus 10 in its simplest formincludes a channel hopper 12 and a sample collector 14. The channelhopper 12 is further depicted in FIG. 2, and the collector 14 is laterdescribed in multiple embodiments herein.

Generally, the channel hopper 12 receives a particulate solids mixture15 from a feeder mechanism 16, stores the mixture to a predeterminedlevel or amount in the channel hopper 12, and then conveys or channelsthe mixture 15 to the collector 14 formed of a plurality mixture samplereceptacles 18. Additional details regarding this apparatus and processwill be described in further detail below.

With regard to FIG. 2, the channel hopper 12 is depicted in accordancewith one example embodiment of the present invention. The channel hopper12 includes a first pair of opposed walls 21 formed of a first wall 20and a second wall 22. The channel hopper 12 further includes a secondpair of opposed walls 25 formed of a third wall 24 and a fourth wall 26.The first pair of opposed walls 21 and the second pair of opposed walls25 couple together to create the channel hopper 12 with a supply opening28 and a discharge opening 30. The supply opening 28 is sufficientlysized to enable supply of the mixture 15 to the channel hopper 12, andthe discharge opening is sufficiently sized to enable discharge of themixture 15 from the channel hopper 12, when desired. As depicted, thesupply opening 28 and the discharge opening 30 extend across a completelength and width of the channel hopper 12. However, one of ordinaryskill in the art will appreciate that the supply opening 28 anddischarge opening 30 need not be as large relative to the channel hopper12 size. Additional panels or walls can be provided to reduce theirrespective sizes, if desired. It shall further be noted that thedischarge opening 30 can have a tapering rectangular shape. However,this is merely representative of one possible shape of the dischargeopening 30 in accordance with one example embodiment of the presentinvention.

The channel hopper 12 is formed of a series of convergently anddivergently angled walls. Looking at FIGS. 2, 3A, 3B, 3C, and 3D, oneexample embodiment of the channel hopper 12 is depicted to illustratethe convergent and divergent relationships. The first pair of opposedwalls 21 are divergently angled relative to each other from the supplyopening 28 toward the discharge opening 30. The purpose of the divergentrelationship is to alter the stress field within the mixture duringdischarge from the channel hopper 12, to promote mass flow with reducedvelocity gradients, in order to maintain the state of segregation assamples are collected. The actual degree to which the divergent anglerelationship occurs can vary depending on the particular application andperhaps the specific mixture 15 being tested. However, generally, thedivergent angle can be greater than about 1 degree from parallel topromote mass flow.

The second pair of opposed walls 25 are convergently angled relative toeach other from the supply opening 28 toward the discharge opening 30.The purpose of the convergent relationship is twofold. The third wall 24(which is proximal to a supply point of the mixture 15 as laterdiscussed) is angled relative to vertical by an amount represented byangle A. The function of angle A is to cause the third wall 24 to be ata sufficient angle such that mixture 15 supplied to the supply opening28 proximal the third wall 24 slides along the first wall toward thedischarge opening 30 and collects within the channel hopper 12 (thechannel hopper having the discharge opening 30 blocked during the fillstage of the process, as later described). However, angle A should notbe so large as to cause a significant velocity gradient of the mixture15. Angle A should be sufficient to merely direct and maintain controlof the flow of the mixture 15 to reduce the occurrence of bouncing,spraying, or other creation of airborne mixture particulates. Thus,angle A is sufficient to control the flow of the mixture into thechannel hopper 12, but does not create a substantial hindrance to theflow of the mixture 15. As the channel hopper 12 sits flat, an examplemeasurement of angle A that often provides the desired functionality isabout 10-15 degrees from vertical. However, during the fill or supply ofthe mixture 15 to the channel hopper 12, the channel hopper 12 ispivoted (as later described) to cause angle A to reduce to about 5degrees from vertical, in accordance with one example implementation.

The fourth wall 26, which makes up the other portion of the second pairof opposed walls 25 is also angled convergently. The purpose of aconvergent slope for the fourth wall 26 is to provide a surface that canform plus or minus 20 degrees in the vicinity of a right angle with anangle of repose R (see FIG. 4) when the channel hopper 12 is in its fillposition, which may require a pivoting of the channel hopper 12 as laterdescribed. This geometry provides a relatively long sliding length forthe mixture during a fill operation, while still providing a reasonablysmall outlet to collect appropriate sized samples.

The first pair of opposed walls 21 are also divergently angled relativeto each other from the third wall 24 toward the fourth wall 26, as canbe seen in FIG. 3B. The purpose of the divergent relationship is tosubstantially minimize or eliminate the frictional surface effects ofthe first wall 20 and the second wall 22 on the flow of the mixture 15as it is supplied to the channel hopper 12 and avalanches to a settledposition. The actual degree to which the divergent angle relationshipoccurs can vary depending on the particular application and perhaps thespecific mixture 15 being tested. However, generally, the divergentangle can be greater than about 1 degree from parallel to substantiallyminimize the frictional effects of the first and second walls 20 and 22on the mixture. One result of the first pair of opposed walls 21 beingdivergently angled is that the supply opening 28 forms an elongatetrapezoidal shape.

Briefly, and with reference to FIG. 1, the channel hopper 12 can haveits overall orientation pivoted in one direction or the other.Specifically, a first pivot positioner 40, a second pivot positioner 42,a third pivot positioner 44, and a fourth pivot positioner 46, can worktogether to orient the channel hopper 12 as desired. As shown in thefigure, the first pivot positioner 40 and the third pivot positioner 44are being utilized to tilt or pivot the channel hopper 12 during a filloperation. The pivoting action enables the variation of the angle A (ofFIG. 3A) relative to vertical, and also the variation of the slope ofthe opposite wall, namely the fourth wall 26, so that avalanchingmixture 15 will approach the fourth wall 26 at about a perpendicularrelationship. Then, after the fill operation is completed, the channelhopper 12 can be moved to the second pivot positioner 42 to orient thechannel hopper 12 in a flat or horizontal orientation for sampling, aslater described. One of ordinary skill in the art will appreciate thatthe first pivot positioner 40, second pivot positioner 42, third pivotpositioner 44, and fourth pivot positioner 46 are merely representativeof one example embodiment. The channel hopper 12 can be pivoted duringthe fill operation using only the third pivot positioner 44 and thefirst pivot positioner 40. If the channel hopper 12 is oriented in theopposite direction, or is filled on the opposite side, then the secondpivot positioner 42 and the fourth pivot positioner 46 can work togetherto provide the appropriate pivot. Accordingly, one of ordinary skill inthe art will appreciate that the illustrated embodiment merelydemonstrates a number of different positioner options, not all of whichare required in any one embodiment.

Returning now to FIGS. 3A-3D, the discharge opening 30 is formed by thecombination of the first wall 20, the second wall 22, the third wall 24,and the fourth wall 26. The combination of the four walls of the channelhopper 12 can come together to form a rectilinear discharge opening 30,or a slightly trapezoidally shaped, or tapering rectangular shaped,discharge opening 30. The discharge opening is sized, dimensioned, andconfigured to support mass flow of the mixture through the channelhopper 12. Because the channel hopper 12 has a relatively smaller width,as viewed from the top, nearer the third wall 24 and a relatively largerwidth nearer the fourth wall 26, the discharge opening 30 can vary inwidth to allow less volumetric flow nearer the third wall 24 and morevolumetric flow nearer the fourth wall 26. This is achieved by having aslight taper or alternatively a trapezoidal shape to the dischargeopening 30, wherein the narrower end is proximal the third wall 24 andthe wider end is proximal the fourth wall 26. Thus, as mixture flowsthrough the channel hopper, there is preferably no change in flowvelocity at the third wall 24 side of the channel hopper 12 relative toflow velocity at the fourth wall 26 side of the channel hopper 12. Itshall be noted that if the cross-sectional area sliced through thechannel hopper 12 at various horizontal locations is substantially thesame (i.e., the convergent and divergent walls combine in some mannerthat results in a consistent length and width across a particularhorizontal slice), then the discharge opening 30 can be a rectilinearshape. Furthermore, one of ordinary skill in the art will appreciatethat the discharge opening 30 can take a number of different forms orshapes to adjust the mass flow rate of the mixture across all sectionsof the channel hopper 12 in accordance with concepts expressed herein.

FIG. 4 is a diagrammatic front view illustration of the channel hopper12 in accordance with one embodiment of the present invention. Thisfigure shows the channel hopper 12 partially filled with mixture 15. Themixture 15 is provided to the channel hopper 12 at a fill region 36,which is essentially proximal the third wall 24, such that the mixture15 can slide down the third wall 24 to fill the channel hopper 12 duringa fill operation. The mixture 15 fills the channel hopper 12 by slidingdown the third wall 24 and impacting with previously supplied mixture,then avalanching down toward the fourth wall 26. As the mixtureavalanches, it does so at an angle of repose R related to the particularproperties of the mixture 15, and the angle at which the channel hopperis oriented or pivoted. The channel hopper 12 can be substantiallytransparent, enabling a user to view the mixture 15 as it collects inthe channel hopper 12. As such, the channel hopper 12 can additionallysupport use of angle of repose markings 34 so that a user may quicklyreference the angle of repose. The angle of repose markings 34 canindicate, for example, angle measurements of between about 20 degreesand about 45 degrees from horizontal during a filling operation when thechannel hopper 12 is pivoted.

When the channel hopper 12 has a sufficient amount of mixture 15contained therein, a series of samples of the mixture 15 can be takenusing the plurality of mixture sample receptacles 18 disposed in thecollector 14 to receive mixture supplied to the channel hopper 12 foranalysis of mixture segregation. Turning now to FIG. 5, the collector 14and the plurality of sample receptacles 18 are shown in accordance withone example embodiment of the present invention. The sample receptacles18 are resident within a shuttle 50. The shuttle 50 is reciprocallyslidable between a first position 52 and a second position 54. When theshuttle is disposed in its first position 52, the plurality of samplereceptacles are disposed beneath the discharge opening 30 of the channelhopper 12, enabling the mixture 15 to flow from the channel hopper 12 tothe plurality of sample receptacles 18. The sample receptacles 18 arebroken into five sections or segments in the illustrative embodiment.However, one of ordinary skill in the art will appreciate that a greateror fewer number of sample receptacles can form the plurality of samplereceptacles 18 to vary the granularity of the sample rate.

As the mixture 15 flows into the plurality of sample receptacles 18, theplurality of sample receptacles fills until it is full, thus stoppingmixture flow. The shuttle is then moved to the second position 54 wherethe user has access to the plurality of sample receptacles 18 and canremove the mixture 15 samples from each of the plurality of samplereceptacles 18 for segregation testing. When the shuttle 50 is in thesecond position 54, the shuttle 50 acts as a channel block, blocking thedischarge opening 30 of the channel hopper 12 so that no mixture 15 canflow. The process is repeated with the shuttle 50 reciprocating betweenfirst and second positions 52 and 54 to remove samples of the mixture 15from the channel hopper 12 until all of the mixture 15 is removed fromthe channel hopper 12, or alternatively, until a sufficient amount isremoved for the desired testing procedure. The arrangement of thesamples receptacles allows for matrix sampling (rows and columns) by thetest apparatus, if desired.

FIGS. 6, 6A, 6B, 6C, 6D, and 6E are illustrations of an alternative, andmore elaborate, implementation to the collector 14 depicted in FIG. 5.In the present example, a collector 14′ provides a more automatedapproach to obtaining the samples of the mixture 15 from the channelhopper 12. The configuration depicted also eliminates free-fall from thechannel hopper 12 into the collector 14, and eliminates counter-flow ofair up through the channel hopper 12, which can otherwise disrupt thesegregation pattern in the channel hopper 12. The channel hopper 12 isnot shown in this figure, but sits positioned atop a fixed base 56 as inother described implementations. A piston channel block 58 is sized anddimensioned to snugly fit within a first receptacle 62 of a firstshuttle 60 (see FIG. 6A) passing through a piston receptacle or secondreceptacle 65 of a second shuttle 64. When it is desired for the mixture15 to flow from the channel hopper 12 to be sampled, the piston channelblock 58 lowers into the second receptacle 65 to reveal the firstreceptacle 62 (see FIG. 6B). The mixture 15 fills the first receptacle62. The first shuttle 60, the second shuttle 64, and the piston channelblock 58 (disposed in the second receptacle 65) reciprocally slide toclose the discharge opening 30. The second shuttle 64 and the pistonchannel block 58 are then fixed in place, while the first shuttle 60with the mixture 15 in the first receptacle 62 continues to reciprocallyslide (see FIG. 6C). The mixture 15 transfers from the first receptacle62 to a plurality of sample receptacles 18 in a third shuttle 68 (seeFIG. 6D). The third shuttle 68 then reciprocally slides over each of aplurality of staggered apertures 72 in a fixed plate 70. As the thirdshuttle 68 slides over the staggered apertures 72, each individualreceptacle of the plurality of sample receptacles 18 deposits the samplemixture 15 into one of a plurality of collection containers 74 (see FIG.6E). Thus, the plurality of staggered apertures 72 aligns with theplurality of mixture sample receptacles 18 to incrementally enable flowof mixture from each of the plurality of mixture sample receptacles 18one at a time into separate collection containers 74 as the thirdshuttle 68 slides over the fixed plate 70.

The mixture samples in each of the collection containers 74 can theneach be analyzed for segregation or other testing. The first shuttle 60,the second shuttle 64, the third shuttle 68, the fixed plate 70, and thepiston channel block 58 then reset to the positions shown in FIG. 6 toprepare for the next sampling of mixture 15 from the channel hopper 12.The return sequence is different from the initial sequence. The thirdshuttle 68 returns to its original position. The piston channel block 58rises to fill the first receptacle 62 making the top face of the pistonchannel block 58 flush with the top of the first shuttle 60. Then, thefirst shuttle 60 and second shuttle 64 return to their original startingposition. In this manner, the mixture 15 does not free-fall into thefirst receptacle 62. One of ordinary skill in the art will appreciatethat the example of FIG. 6 is merely an alternative and more elaboratecollection mechanism relative to the mechanism shown in FIG. 5. However,the present invention is not limited to the two variations of mechanismsdescribed herein. These are simply intended as illustrative ofmechanisms or devices that can form a part of the testing apparatus ofthe present invention to aid in the acquisition of mixture samples fromthe channel hopper 12 in a manner that is predicable, repeatable, andcan obtain samples without substantially disrupting the mixture 15 inthe channel hopper 12.

The collectors 14 and 14′ of FIGS. 5 and 6 are useful in that they canrepeatedly remove samples of mixture 15 from the channel hopper 12without substantially disturbing or disrupting the physical position ofthe solid particles of the mixture relative to one another as they cameto rest in the channel hopper 12. One of ordinary skill in the art willappreciate that other methods for removing the mixture 15 from thehopper may be more disruptive of the mixture 15. For example, if themixture is scooped out from the supply opening 28 of the channel hopper12, then the location of the removed mixture 15 would be filled in withadditional avalanching of the mixture 15, thus highly disrupting themixture 15. Alternatively, if the channel hopper 12 were tilted to pourthe mixture 15 from the supply opening 28, again the mixture 15 as itsettled or collected in the channel hopper 12 would be completelyre-mixed and re-distributed. As such, accurate samples of how themixture 15 came to rest within the channel hopper 12 would not beobtainable. The inventors of the present invention have devised thecollectors 14 and 14′ as described and depicted herein to remove mixturesamples from the discharge opening 30 of the channel hopper 12 in amanner that maintains sufficient order of solid particles in the mixture15 as they are deposited during the fill operation of the channel hopper12. In so doing, the segregation pattern developed within the channelhopper 12 is maintained during the sample collection process. Thecollectors 14 and 14′ further provide the ability to sample the entiremixture 15 contained in the channel hopper 12, in that repeatedhorizontal levels of mixture samples can be removed until the entiremixture 15 is removed from the channel hopper 12. Thus, the samples arehighly demonstrative of the actual segregation of particles within allportions or locations of the channel hopper 12.

The testing apparatus 10 of the present invention as depicted in FIG. 1further includes the feeder mechanism 16. In order to ensure a moreaccurate test of the segregation of solid particles in a mixture 15 as aresult of being loaded into a bin or hopper, it is useful to maintain agood mixture of the solid particles as they are fed to the channelhopper 12. It can be desirable to maintain a steady controlled feed ofthe mixture 15 to the channel hopper 12. Mixtures of solid particles canhave varying pockets of larger or smaller particles if not well mixed.In addition, some feeding mechanisms can cause shearing of the solidparticles, breaking them up into half particles or smaller particles,which can be undesirable. In addition, some mixtures of solid particlescan have relatively high cohesive strengths. The cohesive strength of apowder is a measure of the forces of attraction between the molecules.Mixtures with high cohesive strengths can be subject to clumping of themixture. Accordingly, a feeder mechanism 16 is required that canmaintain a mixture in its well-mixed condition while distributing orsupplying a measurable or predicable amount of the mixture 15 to thechannel hopper 12 for collection and subsequent testing. The feedermechanism 16 should also operate with minimal shearing of the particlesof the mixture 15 during distribution.

Accordingly, the feeder mechanism 16 is depicted in FIGS. 1, 7, and 8,in accordance with one example embodiment of the present invention. Thefeeder mechanism 16 is a minimally-shearing mechanism that regulates andcontrols the supply of the mixture 15 from the supply hopper 78 wherethe mixture is well mixed, to the channel hopper 12 of the testingapparatus 10. The feeder mechanism 16 includes a motor 80 for poweringthe feeder mechanism 16. A fixed bottom plate 82 supports a rotatablyslidable second plate 86. The fixed bottom plate 82 includes a dischargeaperture 84, which provides the mixture 15 to a fill tube 104 that isultimately positioned in the fill region 36 of the channel hopper 12.

The rotatably slidable second plate 86 includes a plurality of passthrough apertures 88 formed with a plurality of dividers 90. In theexample embodiment illustrated, the plurality of pass through apertures88 are disposed about a periphery of the second plate 86, which issubstantially circular in shape. However, one of ordinary skill in theart will appreciate that the plurality of pass through apertures 88 cantake the form of complete holes drilled through the second plate 86, orsome other variation that enables an aperture that passes completelythrough the second plate 86 in a manner that the mixture 15 can passthrough as desired. Furthermore, the shape of the second plate 86 is notrequired to be circular, especially if the second plate 86 continuesoutwardly beyond the path of pass through apertures 88. Accordingly, thepresent invention is not limited to the specific implementation depictedherein. Rather, other equivalent structures are anticipated by thepresent invention, and are therefore included within the scope of thepresent invention.

Referring to FIG. 8, a fixed cam plate 92 is mounted on top of thesecond plate 86, in a manner allowing the second plate 86 to rotaterelative to the cam plate 92. The fixed cam plate 92 has a contouredperiphery 94 formed by an incrementally increasing radial dimension froman inner radius to an outer radius, the outer radius placing thecontoured periphery or perimeter of the cam at about the location of theplurality of pass through apertures 88, such that any mixture depositedon the second plate 86 is pushed outward to the plurality of passthrough apertures 88, and the cam plate 92 at its outermost radialdimension covers the top surface plate portion of the second plate.Further discussion of this relationship is provided below. The fixed camplate 92 further includes a supply port 96 that leads to a depositionaperture 98. The supply port 96 couples with the supply hopper 78 andpasses the mixture to the deposition aperture 98. The depositionaperture 98 deposits the mixture on the second plate 86 with a uniformcross-sectional area. The uniform cross-sectional area enables accurateregulation and control of the amount of mixture 15 ultimately beingsupplied to the channel hopper 12. The cross-sectional area created bythe deposition aperture 98 is sized to regulate the flow rate to bebelow that provided by the pass through apertures 88 to preventoverfilling of the pass through apertures 88.

A fixed top plate 100 is disposed on top of the fixed cam plate 92 andsupports the motor 80. The fixed top plate 100 further includes a supplyaperture 102 that couples the supply hopper 78 with the supply port 96of the fixed cam plate 92, enabling supply of the mixture to thedeposition aperture 98.

In operation, the following process occurs in accordance with oneexample embodiment of the present invention, and as illustrated in FIG.9, as well as with reference to FIGS. 1-8. The well-mixed mixture 15 issupplied to the supply hopper 78. The motor 80 rotates the second plate86 at a desired rate. It has been found with most powder particulatesolid mixtures that a rate of between 2 RPM and 20 RPM is appropriate tokeep a steady flow, but to avoid going too fast and causing the mixture15 to sweep past the discharge aperture 84. One of ordinary skill in theart will appreciate that the specific RPM of the second plate 86 isbased at least in part on the size of the particles in the mixture 15and their respective cohesive strength. In general, it is preferable toproduce a substantially steady stream of mixture flowing to the channelhopper 12. Thus, if the RPM of the second plate 86 is too slow, a pulsedoutput would result and this would be undesirable for most applications.However, one of ordinary skill will appreciate that such pulsedoperation is achievable with the present invention, thus such action isnot beyond the scope of the present invention.

The mixture passes through the supply aperture 102 of the fixed topplate 100 to the supply port 96 in the fixed cam plate 92. The mixture15 continues through to the deposition aperture 98 and as the secondplate 86 rotates, the mixture 15 is deposited on the top of the secondplate 86 in a deposition trail having a uniform cross-section shapedsimilarly to the shape of the deposition aperture 98. In the exampleembodiment, the deposition aperture 98 maintains an arch shape, but anyappropriate shape may be used. The second plate 86 continues itsrotation and the deposition trail brushes along the contoured periphery94 of the fixed cam plate 92. As the deposition trail of the mixture 15continues around the contoured periphery 94 it is progressively pushedradially outwardly until it eventually reaches and falls through theplurality of pass through apertures 88 in the second plate 86. Thesecond plate 86 continues rotation and pushes the mixture 15 in the passthrough apertures 88 to the discharge aperture 84, where the mixture 15falls through to the fill tube 104 and then into the channel hopper 12generally at the fill region 36. This entire supply process is done withminimally-shearing action that provides a substantially steady flow rateof the mixture 15 into the channel hopper 12.

The channel hopper 12, prior to the introduction of the mixture 15, ispivoted up on the end of the third wall 24 to create a slope on thethird wall of about 5 degrees from vertical (see FIG. 9, step 1, angleP). The slope in the pivoted position is closer to vertical than theslope of the third wall 24 when the channel hopper 12 is sitting level,without pivoting. As the mixture 15 passes through the fill tube 104 itmakes minimal contact with the third wall 24 of the channel hopper 12and slides down the third wall 24 until impacting either the channelblocking portion of the shuttle 50 (or piston channel block 58), or asthe mixture collects, other already deposited mixture 15. The mixture 15eventually begins avalanching down toward the fourth wall 26 as thechannel hopper 12 fills with mixture (see FIG. 9, step 2). The angle ofrepose R of the mixture can be visually tracked with the angle of reposemarkings 34 if desired.

Once the mixture 15 substantially fills the channel hopper 12, thefeeder mechanism 16 is shut down to halt the flow of the mixture 15 tothe channel hopper 12. If the channel hopper 12 was pivoted upward forthe filling operation, the channel hopper 12 is moved back down to anun-pivoted condition, where the collector 14 is substantially horizontal(see FIG. 9, step 3). The testing apparatus 10 is then ready for theacquisition of samples from the channel hopper 12. As previouslydiscussed, several different mechanisms and methods can be utilized toobtain samples from the channel hopper 12. For purposes of thisoperational description, the embodiment depicted in FIG. 6 will bereferenced.

During the fill operation, the piston channel block 58 is in placecompletely filling the first receptacle 62, creating the channel blockconfiguration. This enables the mixture 15 to collect in the channelhopper 12. When the fill operation is complete and it is time forsampling to begin, the piston channel block 58 lowers to reveal thefirst receptacle 62. It shall be noted that the piston does not lowerbeyond the bottom surface of the first receptacle 62. Thus, there are nogaps formed between the piston channel block 58 and the first receptacle62. Rather, a chamber is formed within the first receptacle 62, with theonly opening being on the topside of the first receptacle 62 allowingmixture 15 to flow from the channel hopper 12 to the first receptacle62. The first shuttle 60 (in its first position during the filloperation and the lowering of the piston channel block 58), togetherwith the piston channel block 58 and the second shuttle 64, then slidesto a second position. At this second position, the piston channel block58 and second shuttle 64 remain fixed in place. The first shuttle 60 isthen moved to a third position, whereby the first receptacle 62 overlapswith the plurality of sample receptacles 18 in the third shuttle 68. Themixture 15 flows from the first receptacle 62 to the plurality of samplereceptacles 18 (see FIG. 9, step 4). The plurality of sample receptacles18 are walled off between one another, such that sections of the channelhopper 12 can be identified and sectioned out for analytical purposes.The number of sample receptacles utilized is reflective of the level ofgranularity or resolution desired for the particular test. The samplesize is important because it can be customized to equal that needed fora particular analytical test, and thus obviate the need for rifflingand/or sub-sampling, which can skew the results. If two samplereceptacles are utilized, the granularity or resolution is very low, andif twenty or thirty sample receptacles are utilized, the granularity orresolution is quite high. The number of sample receptacles can rangefrom one to a maximum. The maximum number of sample receptacles islimited only by the ability of the mixture 15 to fit in each samplereceptacle. If the width of the sample receptacle is so small or narrowas to not allow all sizes of solid particles in the mixture to fitwithin the sample receptacle, then the number of sample receptacles mustbe reduced until all particles can fit (alternatively, the width of thedischarge opening 30 and total width of the plurality of samplereceptacles can be increased with a re-designed testing apparatus).

Once the plurality of sample receptacles 18 are filled with the mixture15, the third shuttle 68 (in its first position during the transfer ofthe mixture 15 to the plurality of sample receptacles 18) slides towarda second position. As the third shuttle 68 slides, each individualsample receptacle of the plurality of sample receptacles 18 comes acrossone of the plurality of staggered apertures 72 in the fixed plate 70. Aseach sample receptacle overlaps each staggered aperture, the mixture 15flows from the sample receptacle to one of the plurality of collectioncontainers 74 (see FIG. 9, step 5). Thus, each collection container (1A,1B, 1C, 1D, 1E) repeatedly receives mixture samples from a same verticalcolumn of mixture from the channel hopper 12. Additionally, theplurality of collection containers 74 can be emptied, or new containersadded, and their contents quantified and logged so that each horizontalrow of sample taken from the mixture 15 in the channel hopper 12 can beidentified. Referring to FIG. 9, (step 4), the vertical and horizontalgradations indicate each sample section that can be attained,identified, quantified, and tested, using the testing apparatus 10 ofthe present invention.

The testing apparatus 10 of the present invention, and correspondingmethod of use, provides a user with the ability to simulate the internalconditions of a particulate solid collection within a storage hopper.The amount of particulate solid mixture sample required to perform thetest and obtain valid results is substantially less than the amount ofmixture stored in the hopper being simulated (on the order of 1600 Kg).A typical testing apparatus may hold on the order of 35 grams (or about70 ml) of sample mixture. One of ordinary skill in the art willappreciate that the precise weight quantifiers of the hopper beingsimulated and the testing apparatus are merely exemplary. The presentinvention is intended to relate generally to the provision of a testingapparatus that requires substantially less particulate solid mixturesample amounts relative to the storage bin or hopper undergoingsegregation testing. Thus, in instances where the mixture is formed ofrelatively expensive material, the smaller sample sizes (relative to thevolume of material required in previous segregation test methods) arehighly advantageous, because the overall costs of the segregationtesting, especially with regard to material, are dramatically reducedrelative to other testing methods. Furthermore, the testing apparatus 10provides a substantially uniform flow of the mixture as it passesthrough the channel hopper 12 for sampling, thus making the testingapparatus 10 highly accurate in testing the conditions inside a largerhopper collecting the mixture with regard to the occurrence of siftingsegregation. Also, the sample size (as collected from the tester) isimportant because it can be customized to equal that needed for aparticular assay, and thus obviate the need for riffling and/orsub-sampling, which can skew the results

In addition, the testing apparatus of the present invention makes use ofthe feeder mechanism 16, which provides a steady minimally-shearingsupply of the mixture to the channel hopper 12. The feeder mechanism canvary in speed, thus varying flow rate of the mixture as desired. Thefeeder mechanism further operates with minimal sifting segregation ofthe mixture as it passes through the feeder mechanism to the channelhopper 12. Thus, the feeder mechanism provides minimal disruption of themixture from the supply hopper, but enables regulation and control ofthe mixture feed to the channel hopper.

Numerous modifications and alternative embodiments of the presentinvention will be apparent to those skilled in the art in view of theforegoing description. Accordingly, this description is to be construedas illustrative only and is for the purpose of teaching those skilled inthe art the best mode for carrying out the present invention. Details ofthe structure may vary substantially without departing from the spiritof the present invention, and exclusive use of all modifications thatcome within the scope of the appended claims is reserved. It is intendedthat the present invention be limited only to the extent required by theappended claims and the applicable rules of law.

1. A feeder for a mixture of particulate solids, comprising: a fixedbottom plate having a discharge aperture therethrough; a second platerotatably slidable over the bottom plate, having a plurality of passthrough apertures disposed therein, and having its rotational axisspaced to cause the plurality of pass through apertures to passsequentially over the discharge aperture of the bottom plate; adeposition aperture configured to receive the mixture and deposit themixture on the rotatably slidable second plate in a deposited trail asthe second plate rotates; and a fixed cam plate slidably mounted overthe rotatably slidable second plate, the cam plate having a contouredperiphery configured to displace the deposited trail radially andprogressively outward to the pass through apertures of the second plateas the second plate rotates, supplying the mixture forming the depositedtrail to the discharge aperture.
 2. The feeder of claim 1, wherein thedeposition aperture is integral with the cam plate.
 3. The feeder ofclaim 1, wherein the plurality of pass through apertures are uniformlyspaced.
 4. The feeder of claim 1, wherein the plurality of pass throughapertures have equal dimensions to one another.
 5. The feeder of claim1, wherein the plurality of pass through apertures are sizedsufficiently large enough to prohibit the mixture from arching over thepass through aperture due to particle size or particle cohesion.
 6. Thefeeder of claim 1, wherein the plurality of pass through apertures aredisposed in a substantially circular pattern in the second plate.
 7. Thefeeder of claim 1, wherein the second plate has a substantially circularshape.
 8. The feeder of claim 1, wherein the plurality of pass throughapertures are disposed along a periphery of the second plate.
 9. Thefeeder of claim 1, wherein the deposited trail is of uniformcross-section.
 10. The feeder of claim 1, wherein the cam plate isconfigured to displace the deposited trail radially and progressivelyoutward with minimal shearing of the mixture forming the depositedtrail.
 11. The feeder of claim 1, further comprising a supply hopperdisposed to supply the mixture of particulate solids to the feeder. 12.The feeder of claim 1, further comprising a motor configured torotatably drive the second plate.
 13. The feeder of claim 1, wherein thesecond plate rotates at a rate of between about 2 RPM and about 20 RPM.14. The feeder of claim 1, wherein the feeder supplies a substantiallyconstant stream of the mixture through the discharge aperture.